It's just getting an Epic version of the existing quests, with new loot and rares and such. The old Heroic level GH will remain as always. Though I'm not certain that the flagging change will apply for Heroic as well, nor if there's Heroic-level versions of the new gear. Everyone on Lam is testing the epic level versions.

Unfortunately, the DDO forums are down, so I can't check for new info or ask.